One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(9,10)(11,16)(12,21)(13,23)(14,18)(15,20)(17,22)(19,24)(25,26,29,33)(27,34,37,31)(28,38,30,32)(35,40,36,39)(9,11,13,20,14,19,22,12)(10,15,17,16,18,21,23,24)(25,27)(26,31)(28,36)(29,37)(30,35)(32,39)(33,34)(38,40)(1,3,4,8)(2,5,6,7)(11,19)(12,20)(15,21)(16,24)(27,35)(28,30)(31,39)(32,38)(34,40)(36,37)(9,12,22,19,14,20,13,11)(10,16,23,15,18,24,17,21)(25,28,29,30)(26,32,33,38)(27,36,37,35)(31,39,34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.